Improvement in grates and grate-bars



I JOHNC. GRANT.

Improved Grate. 4

Patented Aug. 29, 1871.

JOHN 0. GRANT, OF SALEM, MASSACHUSETTS.

IMPROVEMENT IN GRATES AND GRATE-BARS.

Specification forming part of Letters Patent No. 118,604, dated August 29, 1871.

longitudinal section between two bars. Fig. 3

is a transverse section through the bars, showing the lugs which connect them together in elevation. Fig. 4 is a perspective View, representing a modification of my invention.

My invention consists in a grate provided with a series of projections on its under side, or in a frame having a series of projections on its upper side, placed below the grate, in order that the currents of air which produce the draught may impinge upon the projections and be diverted and prevented from concentrating under-the central surface of the grate, whereby it is kept from being unduly heated, and is consequently more durable than grates as heretofore constructed. FfllhhOIlllOlQ, by the use of my improved grate the fuel is econoinized and its combustion equalized, while the fire is directed into contact with the entire exposed surface of the boiler, thus more rapidly producing evaporation, as desired.

To enable others skilledin the art to understand and use my invention, I will proceed to describe the manner in which I have carried it out.

In the said drawing, A B represent two sections of .a grate in which the bars a are inclined to the sides of the furnace 0. These bars a, are connected together by lugs I) cast in the same piece therewith, the rows of lugs being parallel to each other and to the front and back of the grate for the purpose of preventing unequal shrinkage and expansion. From the under side of each alternate lug extends a projection, c, ta pering slightly inward toward the bottom, the position of the projections on one row of lugs being opposite to the spaces between contiguous projections of the next row, by which arrangement the'currents of air (which in grates as heretofore constructed have been drawn and concentrated in a line under the center of the grate) are I now diffused uniformly under the entire surface ofthe grate, the projections a serving to impede the currents and causing them to flow to one side, as desired, whereby less fuel is required and a more equal combustion nsured, the grate-bars at the center of the grate being also cooled or prevented from being-intensely heated.

It is evident that a frame under the grate may be provided-with projections on its upper or lower side, and where the draught is considerable it is better to have the projections both on the upper and lower sides of the frame, as they more effectually impede or check and equalize the currents flowing into the fire, in which case the projections on the grate could be dispensed with; but both frame and grate might be provided with projections, if desired. I prefer, however, the construction first described. I'do not confine myself to theuse of projections in the construction of grates whose bars are inclined to the front of the grate; but also extend their use to grates in which the bars are curved, and to bars which are at right angles to the front; and the length of the projections as well as their arrangement under the bars may be variedwithout departing from the spirit of my invention.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. A grate whose under side is provided with a series of projections, 12, substantially as and for the purpose set forth.

2. A frame provided with projections on its upper or lower side, or both, inrcombination with a grate, substantially as and for the purpose described. w

Witness my hand this 14th day of July, A. D. 1871.

JOHN 0. GRANT.

Witnessesi N. W. STEARNS, W. J. CAMBRIDGE. 

